Dissociative electron attachment (DEA) to acetic acid in the energy range between about 0 and 13 eV generates as much as nine different fragment ions. The dominant products are CH3COO- and CH2O2- which appear from two closely spaced low energy resonances peaking at 0.75 and 1.5 eV. In view of our ab initio calculation we assign these states as single particle shape resonances associated with the first and second virtual MO, respectively. The electronic and geometrical structure of CH2O2- remains under question, the thermodynamics of the associated DEA reaction, however, predict an exceptionally high stability of this anion. (C) 2003 Published by Elsevier B.V.